Raise ImportError when os.fork does not exist.
diff --git a/Lib/test/test_fork1.py b/Lib/test/test_fork1.py
index 0d20fb3..67e30df 100644
--- a/Lib/test/test_fork1.py
+++ b/Lib/test/test_fork1.py
@@ -10,6 +10,11 @@
 
 import os, sys, time, thread
 
+try:
+    os.fork
+except AttributeError:
+    raise ImportError, "os.fork not defined -- skipping test_fork1"
+
 LONGSLEEP = 2
 
 SHORTSLEEP = 0.5